Synthesis and Application of 18F-FBPA-Fr： a Target Compound for PET Imaging in BNCT & The Chemical Synthesis of 18F-FHBG and Study as Gene Probe in Gene Therapy

• Main Authors: Pi-Fang Chang, 張碧芳
• Other Authors: Hsin-Ell Wang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/47786905243434912067

碩士 === 國立陽明大學 === 放射醫學科學研究所 === 90 === Abstract BNCT (Boron neutron capture therapy) is based on the nuclear reaction that occurs when a stable isotope, 10B, is irradiated with thermal neutrons to yield stripped sown helium nuclei (α-particles) and 7Li nuclei. 10B+ nth  [11B]  4He + 7Li + 2.79MeV(6%)  4He + 7Li* + 2.31MeV(94%)  7Li +  + 0.48MeV The theoretical advantage of BNCT is that it is a binary system, consisting of 10B and thermal neutrons, which when combined together generate high LET radiation capable of selectively destroying tumor cells without significant damage to normal tissues. In order for BNCT to succeed, a critical amount of 10B and a sufficient number of thermal neutrons must be delivered to individual tumor cells. Successful BNCT depends on knowledge of the distribution of boron-containing agents in both tumor and normal tissue. Boronophenylalanine-Fr (BPA-Fr) is one of the promising target compound for BNCT. In this study, radiolabeled 18F2 was produced through the 20Ne(d,)18F reaction, and 18F-AcOF was generated by passing 18F2 through a column which was tightly packed with KOAc•1.5HOAc powder. The effluent containing 18F-AcOF was bubbled into BPA in trifluoroacetic acid, then purified by HPLC and complexed with fructose to obtain 18F-FBPA-Fr. The radiochemical purity of 18F-FBPA-Fr was > 97% and the radiochemical yield of 18F-FBPA-Fr was about 20% (corrected to EOB and based on 18F-AcOF). Fischer 344 rats were inoculated with F98 rat glioma cells in left brain region, and PET scan of 18F-FBPA-Fr were performed on the 13th day after tumor inoculation. The dynamic PET scan of glioma-bearing rats was performed up to 4 hr after injection with 550μCi of 18F-FBPA-Fr. The PET images of F98 glioma-bearing rats revealed specific localization of 18F-FBPA-Fr to tumor at 0.5 to 4 hrs after administration. Since the biodistribution of radiofluronated 18F-FBPA-Fr parallels that of BPA-Fr, 18F-FBPA-Fr can be used with PET to determine the in vivo pharmacokinetics and pharmacodynamics of BPA-Fr biodistribution. The PET scan data will be of practical use for diagnosis of malignancy and direct prediction of the effectiveness of BNCT using BPA-Fr. It would be very valuable for patient selection and pre-BNCT treatment planning.